From: Laura Garcia Liebana <nevola@gmail.com>
Date: Mon, 14 Nov 2016 21:33:34 +0000 (+0100)
Subject: netfilter: nft_hash: validate maximum value of u32 netlink hash attribute
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=abd66e9f3cc50c9c3ba4cf609749374090a2f215;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

netfilter: nft_hash: validate maximum value of u32 netlink hash attribute

Use the function nft_parse_u32_check() to fetch the value and validate
the u32 attribute into the hash len u8 field.

This patch revisits 4da449ae1df9 ("netfilter: nft_exthdr: Add size check
on u8 nft_exthdr attributes").

Fixes: cb1b69b0b15b ("netfilter: nf_tables: add hash expression")
Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---

diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
index baf694de3935..d5447a22275c 100644
--- a/net/netfilter/nft_hash.c
+++ b/net/netfilter/nft_hash.c
@@ -53,6 +53,7 @@ static int nft_hash_init(const struct nft_ctx *ctx,
 {
 	struct nft_hash *priv = nft_expr_priv(expr);
 	u32 len;
+	int err;
 
 	if (!tb[NFTA_HASH_SREG] ||
 	    !tb[NFTA_HASH_DREG] ||
@@ -67,8 +68,10 @@ static int nft_hash_init(const struct nft_ctx *ctx,
 	priv->sreg = nft_parse_register(tb[NFTA_HASH_SREG]);
 	priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]);
 
-	len = ntohl(nla_get_be32(tb[NFTA_HASH_LEN]));
-	if (len == 0 || len > U8_MAX)
+	err = nft_parse_u32_check(tb[NFTA_HASH_LEN], U8_MAX, &len);
+	if (err < 0)
+		return err;
+	if (len == 0)
 		return -ERANGE;
 
 	priv->len = len;